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Relationships come in all shapes and sizes

STARKVILLE, Miss. -- Life is generally better when you have a partner to go with you. Batman has Robin. Han Solo has Chewbacca. Sponge Bob has Patrick.

Of course, Sponge Bob and Patrick are cartoon characters, but there are real wildlife partnerships. The animated movie, “Finding Nemo,” showed clown fish Nemo living among the tentacles of sea anemones. Most animals would not be able to do this, because sea anemones use stinging cells in their tentacles to capture prey. But clown fish have a protective coating that shields them from the stings. Clown fish use this benefit or adaptation to hide safely from predators inside the anemone.

Another example a little closer to home is the long-legged, white birds following cattle or hay tractors around a field. These graceful birds are aptly named cattle egrets for their habit of eating insects flushed out of the tall grass by cows and other grazing animals.

Biologists use the word “symbiosis” to describe a relationship in which two species live closely together. And just like human relationships, some symbiotic relationships in nature are better than others!

One type of symbiosis is called commensalism. In commensalism, one species benefits from the partnership and the other is unaffected. This is the kind of relationship clown fish have with sea anemones, or cattle egrets have with cows or deer. The clown fish and the cattle egrets are helped, but their partners are neither helped nor hurt.

Another kind of symbiosis, parasitism, is less positive. Parasitism describes a situation in which one species in the relationship is helped but the other is harmed.

One of the more unique examples of parasitism is seen in the brown-headed cowbird. A female cowbird does not build her own nest or raise her own young. She lays her eggs in the nests of other kinds of birds, such as cardinals or orioles, where they are incubated by the host mothers. Once the eggs hatch, the hosts feed the cowbird chicks, which grow faster and stronger than their nest mates. Host parents will feed the cowbird nestlings more than their own young, which suffer from less food and may even die of starvation or from being pushed out of the nest.

The last kind of symbiosis is called mutualism. Most of us want our human relationships to be examples of mutualism because both parties benefit.

An excellent example of mutualism in nature is pollination. To reproduce, an individual plant needs to get its pollen to another plant. Some plant species use the wind to carry their pollen, which is why vehicles are coated in yellow during the spring. Pollen carried by the wind doesn’t always land on another plant. To improve their aim, some plants use animals like bees, bats, birds or beetles to carry their pollen. This symbiosis benefits the plant, and, in return for their service, the pollinating animal gets nectar to eat.

Nature has some amazing relationships among the creatures and plants that live all around us. For more information on wildlife, visit http://extension.msstate.edu/ or your local library.

[Editor’s Note: Extension Outdoors is a column authored by several different experts in the Mississippi State University Extension Service.

Editor’s Note: Extension Outdoors is a column authored by several different experts in the Mississippi State University Extension Service.

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